Toner distributor for use with electrophotographic copying machine

ABSTRACT

A toner distributor for use in an electrophotographic copying machine comprising a apertured, flexible plate fixedly connected at one end thereof to the bottom of a toner storage container having an opening in the bottom thereof, a rotatable brush being mounted in the container so as to deform the apertured plate against the bottom of the container as the brush rotates to thereby facilitate distribution of the toner through the plate apertures and thence through the storage container opening to the developing station of the electrophotographic copying machine.

United States Patent 1 1 [111 3,894,510 Eto 1 July 15, 1975 1 TONER DISTRIBUTOR FOR USE WITH Mar. 4, 1 974 Foreign Application Priority Data Fuji Xerox Co., Ltd., Tokyo, Japan Mar. 24, 1973 Japan 48-35017 U.S. Cl 118/308; 118/637 Int. Cl. BOSb 7/14 Field of Search 118/308, 637; 222/410,

222/414, DIG. l

1 References Cited UNITED STATES PATENTS Szostak et a1 118/637 FOREIGN PATENTS OR APPLICATIONS 4,013,231 6/1965 Japan 118/637 Primary Examiner-Louis K. Rimrodt Assistant Examiner-Douglas Salser Attorney, Agent, or Firm-Gerald J. Ferguson, Jr.;

Joseph J. Baker [57] ABSTRACT A toner distributor for use in an electrophotographic copying machine comprising a apertured, flexible plate fixedly connected at one end thereof to the bottom of a toner storage container having an opening in the bottom thereof, a rotatable brush being mounted in the container so as to deform the apertured plate against the bottom of the container as the brush rotates to thereby facilitate distribution of the toner through the plate apertures and thence through the storage container opening to the developing station of the electrophotographic copying machine.

2 Claims, 4 Drawing Figures FIG.2

(PRIOR ART) FIG. I

(PRIOR ART) FIG.4

FIG. 3

TONER DISTRIBUTOR FOR USE WITH ELECTROIPHOTOGRAPI-IIC COPYING MACHINE BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to toner distributors for use with electrophotographic copying machines.

2. Discussion of the Prior Art Generally, in reproducing an original, in electrophotographic copiers, a photosensitive layer having a photoconductive property, e.g., a photosensitive drum, is uniformly, electrically charged in a dark place. and then exposed to light image to dissipate electric charge on those portions exposed to light. An electrostatic latent image corresponding to the original image is thus formed on the photosensitive layer. The latent image is then developed by any of known developing processes such as the cascade developing process or the magnetic brush developing process, to convert the electrostatic latent image into a visible image.

In the cascade developing process and the magnetic brush developing process, the developer usually comprises a granular carrier usually simply called a carrier and particles called toner which adhere to the carrier and are carried therewith. An image thus developed into a visible image is then transferred to a sheet of copy paper or the like and thereafter fixed to finally obtain the copy.

The most important factor determining the image density of a copy is the ratio of carrier quantity to that of the toner, and various types of toner distributors have been specifically designed to keep this ratio constant at all times according to the desires of the operator.

However, the conventional toner distributors employed thus far for practical purposes release a constant quantity of a toner from a toner storage container or tank by opening and closing an aperture, a pipe or a slit at regular intervals of time. However, the ratio of carrier to toner fluctuates depending on the intervals of time between opening and closing the aperture, the pipe or the slit. Further, such systems are complicated and the maintenance and operation thereof are some what difficult.

In an effort to eliminate these defects, a new system for supplying a constant quantity of a toner through apertures in the bottom of a toner storage tank has been described in Japanese Patent No. Ol3,23l 1965, however, it has been experimentally determined that this system also involves some design problems as well as problems relating to the employment thereof for practical purposes. In particular, referring to FIGS. 1 and 2 of the drawing, the toner distributor described in Japanese Patent No. 013,231 I965 includes a brush roll I, which, as it revolves, maintains contact with a distribution plate 2, to thus supply a developing station or apparatus 4, such as a cascade developing apparatus or a magnetic brush developing apparatus, with a toner 3 by way of apertures 5 spaced in plate 2, see FIG. 2. However, distribution plate 2 is made of comparatively hard material, which is difficult to deform; therefore, the distribution plate 2 must be extremely flat. If this is not the case, contact pressure between brush roll I and distribution plate 2 becomes non-uniform over the entire width of the toner storage tank so that uniform supply of toner over the entire width of the developing apparatus is prevented thereby resulting in irregular and uneven density of the toner image.

Thus, since distribution plate 2 must be flat to a high degree of precision in order to obtain a copy free from irregular or uneven image density a serious obstacle is presented to the design and installation thereof thus resulting in increased cost thereof.

SUMMARY OF THE INVENTION A primary object of this invention is to provide a toner distributor, which avoids the above-mentioned defects of the prior art by utilizing a thin, apertured. leafshaped, deformable plate the distribution plate in a brush roll system of the type described above with respect to FIGS. 1 and 2.

Other objects and advantages of this invention will be apparent from a reading of the specification and claims taken with the drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a cross section of a prior art, toner distribu tor of the brush roll type.

FIG. 2 is a perspective of a conventional distribution plate used in the distributor of FIG. 1.

FIG. 3 is a cross section of an illustrative embodiment of a toner distributor in accordance with the present invention.

FIG. 4 is a perspective of the distribution plate used in FIG. 3.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION Referring to FIGS. 3 and 4, there is shown a rotatable brush 11, which is rotated by external means whenever the system requires toner replenishment. The brush is fixedly mounted within toner storage container or tank 15, which has an opening 16 extending across the width of the bottom thereof. A flexible, apertured distribution plate 12 is fixedly connected to the bottom of container 15 at point 17'and assumes a position shown by the phantom lines at 18 when the brush 11 is not in place. With the brush II in place, the strength of the bristles thereof and/or the deformability or flexibility of the plate 12 is such that the plate is forced into the position shown by solid lines at 19, where it remains as long as the brush 11 is in position.

The main feature of the present invention resides in distribution plate 12 which is an elastic, thin, leafshaped, deformable sheet made from a material as Milar, for example. Apertures 20 are drilled therethrough at appropriate spacing as shown in FIG. 4.

Thus, in operation, distribution plate 12 is set in place as shown by the phantom line 18 in FIG. 3, the brush roll 11 is then set in place so as to compress and deform the distribution plate from above. By thus placing brush roll 11, the end portion of brush roll 11 and distribution plate 12 come in contact with each other over their entire widths, so that toner l3 stored in toner storage tank 15 can be supplied into a developing apparatus 14 over the entire width thereof in a uniform manner as the brush 11 rotates.

Thus, in the present invention, an elastic deformable, thin, leaf-shaped sheet is used as the distribution plate 12, whereby contact pressure between brush roll 11 and distribution plate 12 is kept uniform over the entire width of the toner storage tank, in spite of the quite simple constitution thereof. A further advantage of the present invention is that the cost thereof is lower by far than that of any conventional one. Also. the distribution plate 12 can be thin enough that the probability of the apertures 15 being clogged by toner is quite small.

Thus. there has now been described a unique toner distributor for use in an clectrophotographic copying machine in accordance with the invention.

What is claimed is:

1. In a toner distributor for use in an electrophotographic copying machine, said distributor comprising (a) a toner storage container having an apertured plate in the bottom thereof and (b) a rotatable brush rotatably mounted in said container and against said apertured plate so that upon rotation of said brush, toner stored in said container is distributed to a developing station in said electrophotographic copying apparatus through said apertured plate, the improvement comprising. said apertured plate being (a) sufficiently flexi ble so as to be deformed by said brush and (b) connected at one end thereof to the approximate bottom of said toner storage container so that the ends of said rotatable brush are in intimate Contact with the flexible apertured plate across the entire width thereof.

2. The improvement as in claim 1 where said flexible, 

1. In a toner distributor for use in an electrophotographic copying machine, said distributor comprising (a) a toner storage container having an apertured, plate in the bottom thereof and (b) a rotatable brush rotatably mounted in said container and against said apertured plate so that upon rotation of said brush, toner stored in said container is distributed to a developing station in said electrophotographic copying apparatus through said apertured plate, the improvement comprising, said apertured plate being (a) sufficiently flexible so as to be deformed by said brush and (b) connected at one end thereof to the approximate bottom of said toner storage container so that the ends of said rotatable brush are in intimate contact with the flexible, apertured plate across the entire width thereof.
 2. The improvement as in claim 1 where said flexible, apertured plate is a thin, leaf-shaped sheet. 